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No-name <5mW Green Laser Pointer


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Having finally gotten tired of ambiguously pointing with my hand while doing outreach and showing things to the kids, I got a green laser pointer. I got pretty much the cheapest I could find, a no-name job, advertised as 532nm, and less than 5mW (the legal limit on this class of product) from a US-based ebay seller named dear_laser (http://myworld.ebay.com/dear_laser/). The price, including shipping but not batteries, was $8.88, and the seller seems to still have a bunch of lasers at that price point.

Appearance: Nice, comfortable black finish. I don't think there was any nice box for it. I keep unscrewed into two pieces, and on a high shelf, just in case the kids get at it (not that they can't put it together, but it'll slow them down). Has a pleasant heft.

Batteries: Needs two AAAs. I put in some that, I think, were already run-down and they work fine. Haven't had to change them yet, but I haven't used the unit heavily.

Safety: There is a momentary button (i.e., it only shines while the button is held down), which is good for safety, I guess. I do not know whether it has an IR-cutoff filter, so one needs to be careful not to point it near faces (but one would have to be careful even with an IR filter).

Main function: For the first second or so, the laser is at reduced brightness, and then it flares up into a nice green beam. After that, the brightness appears to stay steady (but I never keep it on for very long not to run down the batteries). If you turn it off and turn it back on immediately, the brightness comes instantly. The line of the beam is clearly visible at night, and it makes a great pointer for showing people where a given object one's looking at is. During daylight, only the dot is visible (it is obvious even on a sunlit patch of carpet). I have not tried using it as a finder, except once when I held it to the side of a friend's OTA.

Functioning in cold: I haven't tried the laser in outdoors below approximately 2 C (at around 2 C, it was just fine). As an experiment for this review, I put it in the freezer for five minutes, and took it out cold. It started off at about 1/5 of full brightness, and took about two or three seconds to get to full brightness. I guess if I were using it in the cold, I'd store it in an inner pocket. (A good idea anyway if one is using rechargeable batteries--though I am using alkalines right now.)

Overall: I am guessing that a more expensive laser might not have the very brief warm-up time, but it seems to work fine, and the price is a winner.






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